With the development of modern high-speed railways, the proportion of bridges in railway lines is increasing. When a seismic disaster occurs, the bridge is the most vulnerable part; the use of bridge shock absorption and isolation bearing installations is a practical and feasible shock absorption method, and it is also a kind of anti-seismic technology with mature development and extensive application. At present, the main domestic anti-seismic bearing installations include anti-seismic pot rubber fixing bearings, lead core rubber bearings, friction pendulum seismic isolation bearings, etc.
The anti-seismic pot rubber fixing bearing has a good damping property, and it isolates upper and lower seismic motions through shear deformation, and has the advantages of simple structure, simple manufacturing process, easy installation, and low cost. However, there are also some limitations, specifically, such as low horizontal stiffness and yield strength, low hysteretic performance, lack of vertical and horizontal self-resetting capability, rubber tending to age, no effective constraint on the horizontal displacement between upper and lower plates, an excessive displacement easily leading to the danger of falling bridges.
The lead core rubber bearing has a high energy dissipation capacity, and the internal stress caused by various creep deformations is small, but the shear performance of the bearing is greatly affected by the vertical load. With the increase in lead cores, the recovery ability of the bearing will be weakened, and the bearing cannot play an effective role in seismic reduction and isolation in multi-dimensional random earthquakes.
The friction pendulum seismic reduction and isolation bearing relies on the friction pendulum motion of two curves to achieve seismic reduction and isolation, and reduces the effect of seismic force by prolonging the natural vibration period and friction energy dissipation of the structure. The elevation of the spherical surface changes during swinging, and by raising the upper structure, the potential energy can work and be dissipated; after the earthquake, the bearing can be reset by the weight of the upper structure. However, it will cause a change and increase in the height of the bridge body, which, on the one hand, will affect the smoothness of tracks of railway bridges and affect traffic safety, and on the other hand, will produce additional internal stress, and then affect the overall mechanical structure of bridges, especially not applicable to railway simple bridges or long-span continuous bridges. Moreover, the bearing also has a large spherical radius, a large structure dimension, and high costs.